Mars Spinning Faster, Day Shrinking On Red Planet, Says NASA

Analysis of data collected by NASA's InSight Lander has revealed that Mars is spinning faster. The lander operated for four years before running out of power during its extended mission in December 2022. The findings have been published in a recent paper published in Nature, which scientists say are the most precise measurement ever of Mars' rotation. It found that Mars' rotation on its axis is accelerating by about 4 milliarcseconds each year - corresponding to a shortening of the Martian day by a fraction of a millisecond per year.

Researchers from NASA's Jet Propulsion Laboratory were involved in the study. They are unsure what is causing this speeding up of the Red Planet's rotation, but offer some possible explanations.

They say ice accumulating on the polar caps of the planet could be one of the reasons. They said the shift in a planet's mass can cause it to accelerate a bit like an ice skater spinning with their arms stretched out, then pulling their arms in.

"It's really cool to be able to get this latest measurement - and so precisely. I've been involved in efforts to get a geophysical station like InSight onto Mars for a long time, and results like this make all those decades of work worth it," InSight's principal investigator, Bruce Banerdt of NASA's Jet Propulsion Laboratory, said in a release published on the agency's website.

The data was collected by a radio transponder on the lander and antennas collectively called the Rotation and Interior Structure Experiment, or RISE.

RISE is the latest in the series of equipment sent by Mars, starting with twin Viking landers in the 1970s and the Pathfinder in the 90s. The upgrades added to it allow RISE to capture five times more accurate data than what was available for the Viking landers.